VOLKSWAGEN GOLF DOOR PROBLEM

Your blend door is not closing correctly... either out of adjustment or the flap/door is missing insulation.

Look under the dash (from the passenger side) while moving the heater dial from cold to hot. Look for a
lever at the bottom of the heater box housing... the lever should be moving back and forth as you move the
dial back and forth.

Like in this video: (different year model vehicle but similar operation.